VISHWAKARMA GOVT. ENGG. COLLEGE

FLUID MECHANICS

TOPIC :- TYPES OF FLOW

Prepared by :-

JAYDIP DUDHAT -150173119002 VIKRAM JAYSWAL -150173119003 JAYESH JOGAL -150173119004 JAYDEEP PANSURIYA -150173119005

Fluids in Motion

Fluids in Motion Fluids can move or flow in many ways.

• Water may flow smoothly and slowly in a quiet stream or violently over a waterfall.

• The air may form a gentle breeze or a raging tornado.

• To deal with such diversity, it helps to identify some of the basic types of fluid flow.

Steady or Unsteady Fluid Flow

•In steady flow the velocity of the fluid particles at any point is constant as time passes.

•Unsteady flow exists whenever the velocity at a point in the fluid changes as time passes.

Turbulent Flow •Turbulent flow is an extreme kind of unsteady flow and occurs when there are sharp obstacles or bends in the path of a fast-moving fluid.

•In turbulent flow, the velocity at a point changes erratically from moment to moment, both in magnitude and direction.

Compressible or Incompressible Fluid Flow

Most liquids are nearly incompressible; that is, the density of a liquid remains almost constant as the pressure changes.

To a good approximation, then, liquids flow in an incompressible manner.

In contrast, gases are highly compressible. However, there are situations in which the density of a flowing gas remains constant enough that the flow can be considered incompressible.

Viscous or Nonviscous Fluid Flow •A viscous fluid, such as honey, does not flow readily and is said to have a large viscosity.

•In contrast, water is less viscous and flows more readily; water has a smaller viscosity than honey.

•The flow of a viscous fluid is an energy-dissipating process.

•A fluid with zero viscosity flows in an unhindered manner with no dissipation of energy.

•Although no real fluid has zero viscosity at normal temperatures, some fluids have negligibly small viscosities.

•An incompressible, nonviscous fluid is called an ideal fluid.

Streamline Flow

•When the flow is steady, streamlines are often used to represent the trajectories of the fluid particles.

•A streamline is a line drawn in the fluid such that a tangent to the streamline at any point is parallel to the fluid velocity at that point.

•Steady flow is often called streamline flow.

(a) In the steady flow of a liquid, a colored dye reveals the streamlines. (b) A smoke streamer reveals a streamline pattern for the air flowing around this pursuit cyclist, as he tests his bike for wind resistance in a wind tunnel.

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